Colloids, freezing irreversible

Aluminum hydroxide adjuvant is stable for at least two years when stored at 4—30°C in well-sealed inert containers. It must not be allowed to freeze as the hydrated colloid structure will be irreversibly damaged. 

Not affected by presence of electrolytes Equally good in aqueous and non-aqueous dispersions Equally good in dilute and dense colloid systems Often results in reversible flocculation Good stability with temperature changes Electrolytes result in destabilization Effective especially for aqueous colloidal dispersions Best for dilute colloidal dispersions Often irreversible coagulation is obtained Coagulation often upon freezing... 

Unmodified colloidal silica dispersions stabilized with alkali ions or aluminate-modified colloidal silica dispersions are not stable towards gelling or coagulation upon freezing and subsequent thawing [58]. The particles in such dispersions are irreversibly aggregated and cannot be brought back to a stable colloidal state. Samples of unmodified sihca dispersions and silane-modified sihca dispersions (two different degrees of silane modification) were put in a freezer at -20°C for 24 h [27]. Then they were thawed at room temperature for 16 h and were finally visually inspected to see... 

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